Occupancy indicator

The "occupancy indicator" is device used to indicate whether a room or bed is currently occupied or not.

Indicators for rooms

• indicator states
• 
  "free" outside
• 
  "free" inside
• 
  "occupied" outside
• 
  "occupied" inside

This indicator is used to show whether a privatisable room is occupied or not. Pulling down the toggle attached to the inside of the door hides the "free" state and reveals the "occupied" state on the sign outside. When the toggle is pulled down and the door then closed, the cloth is clamped in the door frame, preserving the "occupied" state. When the door is opened, gravity pulls the block of wood down, returning the sign to the "free" state.

The current design is a 3rd iteration:

• Old bike gear cable is used. It is freely available anywhere bikes are repaired and very durable. (Brake cable can be used, but much stiffer)
• Small wire clamps are used at end junction and to limit the toggle distance for the "occupied" state.
• The cloth is a strip of denim. Made by getting an old pair of large jeans, cutting off one leg, opening up one of the seams, sewing it back together as a straight "tube", cutting off slices and punching a hole at opposite sides of the slice.
• The cloth is tensioned with a a formed metal rod at each end. Made by pressing old spokes against an improvised form (i.e. large nut cut in half + fitting metal rod) in a vice.

• forming tensioner
• 
• 

Previous designs

The initial design was simply a piece of paper and a clothes peg. People simply moved the peg from "free" to "occupied". While this was very simple to implement, it had the disadvantage that people often forgot to move the peg back to "free" when leaving the room! This lead to multiple instances of a room being unused since people assumed someone was in there, and didn't want to disturb by knocking.

The 2nd iteration moved to the gravity-assisted, door-as-a-clamp design currently used. This was done using string instead of cable + cloth. While easier to implement, it had several disadvantages:

• The string would wear out through the constant friction, leading to regular breakages.
• Before fully breaking, the string would often get longer, making it less clear which state the room was in.
• Because of low surface area, the string was hard to clamp, often requiring additional material to be added to the doorframe.
• The string would wear out a channel in the door frame, accelerating the previous issue.